With 78 percent of executives agreeing that the threat of losing business-critical expertise is more of an issue than it was five years ago, it's crucial that companies have a succession plan and get Millennials involved in the process.

Here are five steps to help secure valuable company knowledge and to ensure Millennial leaders have access to past information and expertise that can influence their future decisions.

1. Analyze your workforce. ?

Gather data about your current employees' ages, tenures, salaries, and job types to assess the risk of brain drain. Gain a clear understanding of the retirement picture over the next three to six years. Identify the areas of the business that are most vulnerable to brain drain.

2. Re-examine retention efforts.

If slowing Baby Boomer departures is necessary, re-examine retention policies and benefits that might improve seasoned-worker retention. Benefits could include compressed work schedules, flextime, remote working, phased retirement, and/or sabbaticals.

For example, the retail pharmacy and healthcare company CVS Health provides a "Snowbird" program that encourages older pharmacists and employees in cold climates to spend the winter working in stores in warmer locations. This is a solution that works well for the business because it retains seasoned workers while meeting the demand for extra help in serving customers who also winter in the warmer locations.

3. Prepare and engage potential retirees.

Approach potential retirees and ask for their active involvement in capturing their knowledge. Emphasize their continued value to the organization with the appropriate context, tone, and candor. Be sensitive to the fact that they might be hesitant to the idea of divulging all of their hard-won knowledge. Consider providing incentives for them to share it with Millennials.

If a supportive company environment has been established, the most seasoned leaders and workers will be willing to help prepare the next generation and will take pride in the legacy they can leave behind.

Active involvement is critical from retirees because they possess tacit knowledge that is difficult to replace. Tacit knowledge (as opposed to formal, codified, or explicit knowledge) is the kind of knowledge that is difficult to transfer to another person by means of writing it down or verbalizing it. An example of tacit knowledge is how to speak a language. You probably don't remember formally learning to speak your native language; nor did you formally teach it to your children. It is the kind of knowledge or skill that is acquired by just being around others.

Seasoned workers often have tacit knowledge that they are not even aware that they possess and don't see how valuable it can be to others. Transferring tacit knowledge works best in an established relationship (like parent to child), which is why a healthy relationship between Baby Boomer and Millennial is crucial for knowledge transfer and plugging the brain drain.

Last, 94 percent of employers report that having a succession plan positively impacts their employees' engagement levels. And, according to TransAmerica Center for Retirement Studies, 68 percent of Baby Boomers envision a phased retirement plan. Potential retirees will be grateful and more engaged when a succession plan has been established.

4. Identify emerging leaders.

It's important to establish a Millennial depth chart for the critical positions that are likely to become vacant. At 38 percent, Millennials make up a majority of the 2017 workforce. By 2020, they will be 50 percent, and by 2025, the workplace will be composed of 75 percent Millennials and Generation Z.

It won't be difficult to identify a Millennial eager to lead since 91 percent of Millennials aspire to be leaders. The challenge comes in finding the Millennials who will stick around after the knowledge transfer is complete since 66 percent of Millennials expect to leave their companies by 2020.

Consider reading more chapters in the "Engage" section of this book for strategies to retain Millennial employees. It's important to document and archive as much of the knowledge-transfer content as possible in case Millennials who receive the knowledge decide to exit the company.

Over 90 percent of Millennials say that working at a company with a clear succession plan would "improve" their level of engagement. Why is that? A succession plan provides Millennials with a sense of career advancement and opportunities to learn and grow, and it demonstrates that there is a defined career path--something Millennials crave.

Note that 65 percent of Baby Boomers say that Millennials have sought them out for guidance, and 58 percent of Millennials turn to Baby Boomers, rather than Generation X, for professional advice. Leverage Millennials' natural gravitation toward more seasoned workers and their knack for collaboration to ensure an effective knowledge transfer.

Here are a few other ideas on how to engage Millennials in the knowledge-transfer process:

  • Emphasize the opportunity for mentoring. Seventy-five percent of Millennials want mentors.
  • Stay connected with Millennials to keep them well informed throughout the knowledge-transfer process.
  • Tie knowledge-transfer opportunities to the larger company mission. Millennials want to make an impact and to be part of the growth.

By actively facilitating the transfer of knowledge and skills from Baby Boomers to Millennials, companies can mitigate the effects of brain drain and prepare Millennials for important leadership roles.

5. Initiate knowledge transfer.

Consider using a few of these knowledge-transferring approaches to combat brain drain and to ensure a successful succession plan.